1. Field of the Invention
This invention relates to medical symptom detection and more particularly relates to seizure symptom detection and warning.
2. Description of the Related Art
Epilepsy and seizures affect nearly three million Americans of all ages, at an estimated annual cost of $15.5 billion in direct and indirect costs. Approximately 200,000 new cases of seizures and epilepsy occur each year. Ten percent of the American population will experience a seizure in their lifetime. Three percent will develop epilepsy by age 75. Annually, approximately five percent of these visit an emergency department due to seizure related injuries, particularly head injuries. Sudden Unexplained Death in Epilepsy Persons (“SUDEP”) has an annual incidence as high as one percent in those with risk factors, including long-term uncontrolled generalized tonic-clonic seizures. SUDEP is most often an un-witnessed nocturnal event. Caregivers can provide timely intervention and treatment for some seizures by giving a “rescue” drug, performing cardiopulmonary resuscitation, (“CPR”), or by calling paramedics. However, there is no readily usable device to warn caregivers when a person with epilepsy is having a seizure or an adverse event associated with a seizure, even though people are particularly susceptible to injury while having a seizure.
Typically, Electroencephalography (“EEG”), a measurement of electrical activity along the scalp produced by the firing of neurons within the brain, is used as the primary diagnostic tool to detect a seizure and to diagnose epilepsy. Epileptic activity can create clear abnormalities on a standard EEG study. Physicians depend almost exclusively upon EEG to determine the pre-ictal, ictal, and post-ictal status of a seizure, that is, determining the starting and ending points of a seizure by measuring the beginning and ending of the abnormal brain electrical activity associated with the seizure. In non-clinical settings, an EEG is not a practical sensor for use as a seizure detection device. It is obtrusive, cumbersome, and would not be worn by patients in home, work, or school settings.